Automatic Focus Adjustment for Bound Document Scanning
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Solution Overview
Problem
Existing methods for scanning bound documents often result in poor image quality due to focus issues and physical stress on the document, especially when using traditional flat-bed scanners, and fail to maintain accurate focus as pages are turned during scanning.
Innovation Solution
A document-imaging device with an automatic focus mechanism that uses a light pattern source and optical sensor to adjust the camera position based on the varying thickness of pages, ensuring consistent focus throughout the scanning process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a traditional flat-bed platen scanner is used to scan bound documents, then the document can be scanned in a face-down position, but force must be applied to the spine or binding which can damage the document and image quality deteriorates due to loss of focus and distortion from page curvature
Solution Approach 1:
The patent inverts the traditional scanning approach by scanning documents in face-up position rather than face-down. The platen-less scanner captures images from above the document surface, eliminating the need to apply force to the spine or binding region, thereby preventing physical damage while maintaining scanning functionality
Solution Approach 2:
The patent replaces the mechanical flat-bed platen system with a platen-less optical system. Instead of using a physical platen that requires mechanical contact and force application, the system uses optical sensors and image capture devices positioned above the document to acquire images without mechanical stress
2Object-affected harmful factors
If a platen-less scanner is used to capture images in face-up position, then no additional stress is applied to the binding region, but the pages may become out of focus during scanning as pages are flipped
Solution Approach 1:
The patent implements a dynamic focus adjustment system that continuously adapts to changing page positions during scanning. The focus mechanism responds to the dynamic state of pages as they are flipped or repositioned, maintaining sharp focus throughout the scanning process rather than using a static focus setting
Solution Approach 2:
The patent employs a feedback mechanism where the system detects page position or thickness variations and automatically adjusts focus accordingly. This closed-loop control ensures that focus remains optimal even as document conditions change during the scanning process
3Productivity
If manual lifting and repositioning of bound documents is performed after each page scan, then complete scanning can be achieved, but the process becomes tedious and time-consuming
Solution Approach 1:
The patent implements an automatic page-turning mechanism that enables the document to be processed through the scanning system without manual intervention. The system autonomously flips pages and maintains proper positioning, eliminating the need for operators to manually lift and reposition documents after each scan
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution maintains image sharpness and reduces physical stress on documents by automatically adjusting the camera focus in response to changes in page thickness, improving image quality and scanning efficiency for bound documents.
Implementation Method 1
The light pattern source projects a predetermined light pattern onto a page of the document object being imaged. The optical sensor senses the light pattern projected onto the page being imaged.
Data Source
AI summary
Systems and methods for automatically focusing an image capture device on a page of a document object. A predetermined light pattern is projected onto the page being imaged. The light pattern varies as a function of the separation of the page being imaged from the end page. The light pattern projected onto the page being imaged is sensed. Based on the sensed light pattern, the image capture device is focused on the page being imaged.